Touch lightly Nature's sweet Guitar — Lyre-Bird

Touch lightly Nature's sweet Guitar
Unless thou know'st the Tune
Or every Bird will point at thee
Because a Bard too soon-
(F.1403/J.1389)
[1] Guitar:: a lute with six strings used to accompany lyrics, a hint on lyre. Touch, Guitar:: to compose a lyric. lightly:: not seriously. Nature:: human nature.
[2] Tune:: disposition, temper of the society or literary world.
[3] Bird:: an exceptionally smart or accomplished person, frequently ironical (OED 4b). Guitar and bird hints at lyre-bird.
[4] a Bard too soon:: Dickinson's confidence in seeing herself a bardess. Her poems were accused by every bird, smart and accomplished person, for she didn't know the tune of the literary world.